﻿using System;
using System.Collections;
using System.Data;
using System.Data.OleDb;


/// <summary>
/// 数据访问基础类(基于OleDb) 
/// 可以用户可以修改满足自己项目的需要。
/// Copyright (C) Maticsoft
/// </summary>
public abstract class DbHelperOleDb
{
    //数据库连接字符串(web.config来配置)，可以动态更改connectionString支持多数据库.		
    public static string connectionString = PubConstant.ConnectionString;

    #region 公用方法

    public static int GetMaxID(string FieldName, string TableName)
    {
        string strsql = "select max(" + FieldName + ")+1 from " + TableName;
        object obj = GetSingle(strsql);
        if (obj == null)
        {
            return 1;
        }
        else
        {
            return int.Parse(obj.ToString());
        }
    }
    public static bool Exists(string strSql)
    {
        object obj = GetSingle(strSql);
        int cmdresult;
        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
        {
            cmdresult = 0;
        }
        else
        {
            cmdresult = int.Parse(obj.ToString());
        }
        if (cmdresult == 0)
        {
            return false;
        }
        else
        {
            return true;
        }
    }
    public static bool Exists(string strSql, params OleDbParameter[] cmdParms)
    {
        object obj = GetSingle(strSql, cmdParms);
        int cmdresult;
        if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
        {
            cmdresult = 0;
        }
        else
        {
            cmdresult = int.Parse(obj.ToString());
        }
        if (cmdresult == 0)
        {
            return false;
        }
        else
        {
            return true;
        }
    }

    #endregion

    #region  执行简单SQL语句

    /// <summary>
    /// 执行SQL语句，返回影响的记录数
    /// </summary>
    /// <param name="SQLString">SQL语句</param>
    /// <returns>影响的记录数</returns>
    public static int ExecuteSql(string SQLString)
    {
        using (OleDbConnection connection = new OleDbConnection(connectionString))
        {
            using (OleDbCommand cmd = new OleDbCommand(SQLString, connection))
            {
                try
                {
                    connection.Open();
                    int rows = cmd.ExecuteNonQuery();
                    return rows;
                }
                catch (System.Data.OleDb.OleDbException E)
                {
                    connection.Close();
                    throw new Exception(E.Message);
                }
            }
        }
    }

    /// <summary>
    /// 执行多条SQL语句，实现数据库事务。
    /// </summary>
    /// <param name="SQLStringList">多条SQL语句</param>		
    public static void ExecuteSqlTran(ArrayList SQLStringList)
    {
        using (OleDbConnection conn = new OleDbConnection(connectionString))
        {
            conn.Open();
            OleDbCommand cmd = new OleDbCommand();
            cmd.Connection = conn;
            OleDbTransaction tx = conn.BeginTransaction();
            cmd.Transaction = tx;
            try
            {
                for (int n = 0; n < SQLStringList.Count; n++)
                {
                    string strsql = SQLStringList[n].ToString();
                    if (strsql.Trim().Length > 1)
                    {
                        cmd.CommandText = strsql;
                        cmd.ExecuteNonQuery();
                    }
                }
                tx.Commit();
            }
            catch (System.Data.OleDb.OleDbException E)
            {
                tx.Rollback();
                throw new Exception(E.Message);
            }
        }
    }
    /// <summary>
    /// 执行带一个存储过程参数的的SQL语句。
    /// </summary>
    /// <param name="SQLString">SQL语句</param>
    /// <param name="content">参数内容,比如一个字段是格式复杂的文章，有特殊符号，可以通过这个方式添加</param>
    /// <returns>影响的记录数</returns>
    public static int ExecuteSql(string SQLString, string content)
    {
        using (OleDbConnection connection = new OleDbConnection(connectionString))
        {
            OleDbCommand cmd = new OleDbCommand(SQLString, connection);
            System.Data.OleDb.OleDbParameter myParameter = new System.Data.OleDb.OleDbParameter("@content", OleDbType.VarChar);
            myParameter.Value = content;
            cmd.Parameters.Add(myParameter);
            try
            {
                connection.Open();
                int rows = cmd.ExecuteNonQuery();
                return rows;
            }
            catch (System.Data.OleDb.OleDbException E)
            {
                throw new Exception(E.Message);
            }
            finally
            {
                cmd.Dispose();
                connection.Close();
            }
        }
    }
    /// <summary>
    /// 向数据库里插入图像格式的字段(和上面情况类似的另一种实例)
    /// </summary>
    /// <param name="strSQL">SQL语句</param>
    /// <param name="fs">图像字节,数据库的字段类型为image的情况</param>
    /// <returns>影响的记录数</returns>
    public static int ExecuteSqlInsertImg(string strSQL, byte[] fs)
    {
        using (OleDbConnection connection = new OleDbConnection(connectionString))
        {
            OleDbCommand cmd = new OleDbCommand(strSQL, connection);
            System.Data.OleDb.OleDbParameter myParameter = new System.Data.OleDb.OleDbParameter("@fs", OleDbType.Binary);
            myParameter.Value = fs;
            cmd.Parameters.Add(myParameter);
            try
            {
                connection.Open();
                int rows = cmd.ExecuteNonQuery();
                return rows;
            }
            catch (System.Data.OleDb.OleDbException E)
            {
                throw new Exception(E.Message);
            }
            finally
            {
                cmd.Dispose();
                connection.Close();
            }
        }
    }

    /// <summary>
    /// 执行一条计算查询结果语句，返回查询结果（object）。
    /// </summary>
    /// <param name="SQLString">计算查询结果语句</param>
    /// <returns>查询结果（object）</returns>
    public static object GetSingle(string SQLString)
    {
        using (OleDbConnection connection = new OleDbConnection(connectionString))
        {
            using (OleDbCommand cmd = new OleDbCommand(SQLString, connection))
            {
                try
                {
                    connection.Open();
                    object obj = cmd.ExecuteScalar();
                    if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                    {
                        return null;
                    }
                    else
                    {
                        return obj;
                    }
                }
                catch (System.Data.OleDb.OleDbException e)
                {
                    connection.Close();
                    throw new Exception(e.Message);
                }
            }
        }
    }
    /// <summary>
    /// 执行查询语句，返回OleDbDataReader
    /// </summary>
    /// <param name="strSQL">查询语句</param>
    /// <returns>OleDbDataReader</returns>
    public static OleDbDataReader ExecuteReader(string strSQL)
    {
        OleDbConnection connection = new OleDbConnection(connectionString);
        OleDbCommand cmd = new OleDbCommand(strSQL, connection);
        try
        {
            connection.Open();
            OleDbDataReader myReader = cmd.ExecuteReader();
            return myReader;
        }
        catch (System.Data.OleDb.OleDbException e)
        {
            throw new Exception(e.Message);
        }

    }
    /// <summary>
    /// 执行查询语句，返回DataSet
    /// </summary>
    /// <param name="SQLString">查询语句</param>
    /// <returns>DataSet</returns>
    public static DataSet Query(string SQLString)
    {
        using (OleDbConnection connection = new OleDbConnection(connectionString))
        {
            DataSet ds = new DataSet();
            try
            {
                connection.Open();
                OleDbDataAdapter command = new OleDbDataAdapter(SQLString, connection);
                command.Fill(ds, "ds");
            }
            catch (System.Data.OleDb.OleDbException ex)
            {
                throw new Exception(ex.Message);
            }
            return ds;
        }
    }


    #endregion

    #region 执行带参数的SQL语句

    /// <summary>
    /// 执行SQL语句，返回影响的记录数
    /// </summary>
    /// <param name="SQLString">SQL语句</param>
    /// <returns>影响的记录数</returns>
    public static int ExecuteSql(string SQLString, params OleDbParameter[] cmdParms)
    {
        using (OleDbConnection connection = new OleDbConnection(connectionString))
        {
            using (OleDbCommand cmd = new OleDbCommand())
            {
                try
                {
                    PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                    int rows = cmd.ExecuteNonQuery();
                    cmd.Parameters.Clear();
                    return rows;
                }
                catch (System.Data.OleDb.OleDbException E)
                {
                    throw new Exception(E.Message);
                }
            }
        }
    }


    /// <summary>
    /// 执行多条SQL语句，实现数据库事务。
    /// </summary>
    /// <param name="SQLStringList">SQL语句的哈希表（key为sql语句，value是该语句的OleDbParameter[]）</param>
    public static void ExecuteSqlTran(Hashtable SQLStringList)
    {
        using (OleDbConnection conn = new OleDbConnection(connectionString))
        {
            conn.Open();
            using (OleDbTransaction trans = conn.BeginTransaction())
            {
                OleDbCommand cmd = new OleDbCommand();
                try
                {
                    //循环
                    foreach (DictionaryEntry myDE in SQLStringList)
                    {
                        string cmdText = myDE.Key.ToString();
                        OleDbParameter[] cmdParms = (OleDbParameter[])myDE.Value;
                        PrepareCommand(cmd, conn, trans, cmdText, cmdParms);
                        int val = cmd.ExecuteNonQuery();
                        cmd.Parameters.Clear();

                        trans.Commit();
                    }
                }
                catch
                {
                    trans.Rollback();
                    throw;
                }
            }
        }
    }


    /// <summary>
    /// 执行一条计算查询结果语句，返回查询结果（object）。
    /// </summary>
    /// <param name="SQLString">计算查询结果语句</param>
    /// <returns>查询结果（object）</returns>
    public static object GetSingle(string SQLString, params OleDbParameter[] cmdParms)
    {
        using (OleDbConnection connection = new OleDbConnection(connectionString))
        {
            using (OleDbCommand cmd = new OleDbCommand())
            {
                try
                {
                    PrepareCommand(cmd, connection, null, SQLString, cmdParms);
                    object obj = cmd.ExecuteScalar();
                    cmd.Parameters.Clear();
                    if ((Object.Equals(obj, null)) || (Object.Equals(obj, System.DBNull.Value)))
                    {
                        return null;
                    }
                    else
                    {
                        return obj;
                    }
                }
                catch (System.Data.OleDb.OleDbException e)
                {
                    throw new Exception(e.Message);
                }
            }
        }
    }

    /// <summary>
    /// 执行查询语句，返回OleDbDataReader
    /// </summary>
    /// <param name="strSQL">查询语句</param>
    /// <returns>OleDbDataReader</returns>
    public static OleDbDataReader ExecuteReader(string SQLString, params OleDbParameter[] cmdParms)
    {
        OleDbConnection connection = new OleDbConnection(connectionString);
        OleDbCommand cmd = new OleDbCommand();
        try
        {
            PrepareCommand(cmd, connection, null, SQLString, cmdParms);
            OleDbDataReader myReader = cmd.ExecuteReader();
            cmd.Parameters.Clear();
            return myReader;
        }
        catch (System.Data.OleDb.OleDbException e)
        {
            throw new Exception(e.Message);
        }

    }

    /// <summary>
    /// 执行查询语句，返回DataSet
    /// </summary>
    /// <param name="SQLString">查询语句</param>
    /// <returns>DataSet</returns>
    public static DataSet Query(string SQLString, params OleDbParameter[] cmdParms)
    {
        using (OleDbConnection connection = new OleDbConnection(connectionString))
        {
            OleDbCommand cmd = new OleDbCommand();
            PrepareCommand(cmd, connection, null, SQLString, cmdParms);
            using (OleDbDataAdapter da = new OleDbDataAdapter(cmd))
            {
                DataSet ds = new DataSet();
                try
                {
                    da.Fill(ds, "ds");
                    cmd.Parameters.Clear();
                }
                catch (System.Data.OleDb.OleDbException ex)
                {
                    throw new Exception(ex.Message);
                }
                return ds;
            }
        }
    }


    private static void PrepareCommand(OleDbCommand cmd, OleDbConnection conn, OleDbTransaction trans, string cmdText, OleDbParameter[] cmdParms)
    {
        if (conn.State != ConnectionState.Open)
            conn.Open();
        cmd.Connection = conn;
        cmd.CommandText = cmdText;
        if (trans != null)
            cmd.Transaction = trans;
        cmd.CommandType = CommandType.Text;//cmdType;
        if (cmdParms != null)
        {
            foreach (OleDbParameter parm in cmdParms)
                cmd.Parameters.Add(parm);
        }
    }

    #endregion



}

